redDot.swift

func redCircleAnimation() {
        let startingPoint = CGPoint(x: 0.0, y: DeviceScreen.main.centreY)
        //Red view
        self.redDotView.layer.cornerRadius = self.redDotView.frame.width/2
        self.redDotView.clipsToBounds = true
        self.redDotView.center = startingPoint
        
        //The path
        let bezierPath = UIBezierPath()
        bezierPath.move(to: startingPoint)
        
        //OPTIONS
        //Curve
        bezierPath.addCurve(to: CGPoint(x: DeviceScreen.main.width, y: DeviceScreen.main.centreY), controlPoint1: CGPoint(x: DeviceScreen.main.centreX, y: (DeviceScreen.main.centreY + 50.0)), controlPoint2: CGPoint(x: DeviceScreen.main.centreX, y: (DeviceScreen.main.centreY - 50.0)))
        
        bezierPath.addLine(to: CGPoint(x: DeviceScreen.main.width, y: 0.0))
        bezierPath.addLine(to: CGPoint(x: 0.0, y: 0.0))
        bezierPath.addLine(to: startingPoint)
        
        //The animation
        let animation = CAKeyframeAnimation(keyPath: #keyPath(CALayer.position))
        animation.path = bezierPath.cgPath
        animation.calculationMode = CAAnimationCalculationMode.paced
        animation.repeatCount = HUGE
        animation.duration = 5.0
        
        //The layer
        let shapeLayer = CAShapeLayer()
        shapeLayer.path = bezierPath.cgPath
        shapeLayer.fillColor = UIColor.clear.cgColor
        shapeLayer.strokeColor = UIColor.red.cgColor
        shapeLayer.lineWidth = 1.0
        
        view.layer.addSublayer(shapeLayer)
        
        self.redDotView.layer.add(animation, forKey: nil)
    }